Xiang Mingtao, Xiao Chiwei, Feng Zhiming, Ma Qin
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; Institute of Digital Agriculture, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; Institute of Land Science and Property, School of Public Affairs, Zhejiang University, Hangzhou 310058, China.
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2023 Dec 1;902:166456. doi: 10.1016/j.scitotenv.2023.166456. Epub 2023 Aug 20.
Fire occurrence is synonymous to terrestrial ecosystems and an important component of the Earth system. Climate change, vegetation characteristics, and human activity regulate fire occurrence and spread, however, fires also interact with them in multiple ways. Due to the complicated mechanisms of interactions between fire and land use or cover, the spatial distribution, change trends and land use or cover types of fire occurrences exist wide discrepancies in different regions or countries around the world. Therefore, the quantitative and spatial relationship and differences between fire and land use or cover at the global scale remain poorly understood systematically. Here, we combine active fire and land cover products during 2001-2020 to explore the spatio-temporal features, trends, and types of active fires from global to continental scales. Globally, the annual changes of monthly active fire occurrences kept a dramatic increase in first two or three years but a circuitous decrease since then. Most areas prevailingly experienced active fires for once to five times, a small part of areas clustered in Africa, Southeast Asia, and South America experienced active fires for over five times in the last 20-years. In particular, above 60 % of active fires (re-)occurred in forest and 20-25 % in cropland, whereas grassland and construction land only accounted for about 5 % and less than 2 % respectively. Driven by active fires, the conversion of forest to cropland accounted for nearly 60 % and the transition of cropland to forest (about 10 %) followed and formed an interactive circle. Our findings improve the understanding of fire-land cover change interactions, particularly agricultural expansion and forest loss driven by active fires. Future efforts on agricultural expansion, urban safety, carbon sequestration and biodiversity conservation should take the results of this research into account.
火灾发生是陆地生态系统的同义词，也是地球系统的重要组成部分。气候变化、植被特征和人类活动调节着火灾的发生和蔓延，然而，火灾也以多种方式与它们相互作用。由于火灾与土地利用或覆盖之间相互作用的机制复杂，火灾发生的空间分布、变化趋势以及土地利用或覆盖类型在世界不同地区或国家存在很大差异。因此，全球尺度上火灾与土地利用或覆盖之间的定量和空间关系及差异仍缺乏系统的深入了解。在此，我们结合2001 - 2020年期间的活跃火灾和土地覆盖产品，探讨从全球到大陆尺度活跃火灾的时空特征、趋势和类型。在全球范围内，月度活跃火灾发生次数的年变化在前两三年急剧增加，但此后呈迂回下降趋势。大多数地区主要经历一到五次活跃火灾，在过去20年中，非洲、东南亚和南美洲的一小部分地区经历了五次以上的活跃火灾。特别是，超过60%的活跃火灾（重新）发生在森林中，20 - 25%发生在农田中，而草地和建设用地分别仅占约5%和不到2%。在活跃火灾的驱动下，森林向农田的转变占近60%，随后农田向森林的转变（约10%）并形成了一个互动循环。我们的研究结果增进了对火灾 - 土地覆盖变化相互作用的理解，特别是活跃火灾驱动的农业扩张和森林损失。未来在农业扩张、城市安全、碳固存和生物多样性保护方面的努力应考虑本研究的结果。
